The bottom sheets on which incontinent patients lie and the crib sheets on which infants lie are frequently soiled and changed several times a day. The prior art bottom sheets for incontinents and crib sheet for infants are generally not moisture proof but are formed from a soft material such as cotton for the comfort of the user. A separate moisture proof pad or sheet is then required to protect the mattress. See, for example, U.S. Pat. No. 1,621,149 issued Mar. 15, 1927 to Blissitt for MATTRESS AND BED PROTECTOR, U.S. Pat. No. 3,530,487 issued Sept. 22, 1970 to Beer for BEDCLOTHES, and U.S. Pat. No. 3,570,026 issued Mar. 16, 1971 to Allison for BABY BED SHEET WITH REMOVABLE PANEL.
Blissitt discloses (column 1, lines 14-16), but does not illustrate, a bottom sheet of the bed just above his mattress protector 10.
Allison discloses (column 1, line 70 through column 3, line 3), but does not illustrate, a quilted absorbent pad that may be placed over the mattress to protect it before the sheet 16 is attached to its retainer 14.
Beer shows a separate moisture proof pad 14 protecting the mattress beneath a bottom sheet 23.
In each of these pieces of prior art, the moisture proof mattress protector is underneath a pervious bed sheet and becomes soiled when the bed sheet becomes soiled. Consequently, the soiled bed sheet and the soiled mattress protector must both be removed from the bed, must both be washed and must both be replaced on the bed. This is an unpleasant and time consuming task.
Blissitt seeks to relieve the unpleasantness and reduce the time by putting straps on the mattress protector to facilitate its removal and replacement when soiled. But the mattress protector becomes soiled when the sheet is soiled and the soiled sheet and the soiled mattress protector must be removed, washed, and separately replaced.
Beer seeks to relieve the unpleasantness and reduce the time of making up a bed by fastening both the moisture proof mattress protector 14 and the bottom sheet 23 to the mattress or to a mattress cover with zippers or Velcro fasteners and putting an elastic band between the mattress and the top sheet so the user can move about the bed freely without dislodging the bed sheets. But the mattress protector becomes soiled when the sheet is soiled and the soiled sheet 23 and the soiled mattress protector 14 must be removed, washed, and separately replaced.
Allison seeks to relieve the unpleasantness and reduce the time by using a retainer encircling the mattress and a sheet overlying the mattress and connected by zippers to the end edges of the retainer on top of the mattress so the mattress need not be lifted when changing a soiled sheet. But Allison's quilted absorbent pad that may underlie the sheet to protect the mattress will become soiled when the sheet is soiled, and the soiled sheet and the soiled pad must be removed, washed, and separately replaced.
U.S. Pat. No. 4,704,753 issued Nov. 10, 1987 to Lunt for FITTED CRIB OR BED SHEET shows a sheet made of synthetic plastic material having an absorbent top layer laminated to a liquid impermeable backing film to protect the mattress when a crib or bed occupant wets the sheet. Only the soiled sheet need be removed and replaced, which is an improvement over the cited prior art. But, the fitted moisture proof sheet of Lunt is cut and shaped to be tucked around and removed from about the sides and ends of the mattress, which is a time consuming disadvantage overcome by the present invention. This disadvantage is heightened when the crib is equipped with bumper guards, which interfere with the removal and installation of Lunt's fitted sheet.